dma-mapping: zero memory returned from dma_alloc_*

If we want to map memory from the DMA allocator to userspace it must be
zeroed at allocation time to prevent stale data leaks.   We already do
this on most common architectures, but some architectures don't do this
yet, fix them up, either by passing GFP_ZERO when we use the normal page
allocator or doing a manual memset otherwise.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Acked-by: Sam Ravnborg <sam@ravnborg.org> [sparc]

12 files changed, 16 insertions, 13 deletions

diff --git a/arch/alpha/kernel/pci_iommu.c b/arch/alpha/kernel/pci_iommu.c
index e1716e0d92fd..aa0f50d0f823 100644
--- a/arch/alpha/kernel/pci_iommu.c
+++ b/arch/alpha/kernel/pci_iommu.c
@@ -443,7 +443,7 @@ static void *alpha_pci_alloc_coherent(struct device *dev, size_t size,
 	gfp &= ~GFP_DMA;
 
 try_again:
-	cpu_addr = (void *)__get_free_pages(gfp, order);
+	cpu_addr = (void *)__get_free_pages(gfp | __GFP_ZERO, order);
 	if (! cpu_addr) {
 		printk(KERN_INFO "pci_alloc_consistent: "
 		       "get_free_pages failed from %pf\n",
diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index db203ff69ccf..1525ac00fd02 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -33,7 +33,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	 */
 	BUG_ON(gfp & __GFP_HIGHMEM);
 
-	page = alloc_pages(gfp, order);
+	page = alloc_pages(gfp | __GFP_ZERO, order);
 	if (!page)
 		return NULL;
 
diff --git a/arch/c6x/mm/dma-coherent.c b/arch/c6x/mm/dma-coherent.c
index 01305c787201..75b79571732c 100644
--- a/arch/c6x/mm/dma-coherent.c
+++ b/arch/c6x/mm/dma-coherent.c
@@ -78,6 +78,7 @@ static void __free_dma_pages(u32 addr, int order)
 void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 		gfp_t gfp, unsigned long attrs)
 {
+	void *ret;
 	u32 paddr;
 	int order;
 
@@ -94,7 +95,9 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 	if (!paddr)
 		return NULL;
 
-	return phys_to_virt(paddr);
+	ret = phys_to_virt(paddr);
+	memset(ret, 0, 1 << order);
+	return ret;
 }
 
 /*
diff --git a/arch/m68k/kernel/dma.c b/arch/m68k/kernel/dma.c
index e99993c57d6b..b4aa853051bd 100644
--- a/arch/m68k/kernel/dma.c
+++ b/arch/m68k/kernel/dma.c
@@ -32,7 +32,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 	size = PAGE_ALIGN(size);
 	order = get_order(size);
 
-	page = alloc_pages(flag, order);
+	page = alloc_pages(flag | __GFP_ZERO, order);
 	if (!page)
 		return NULL;
 
diff --git a/arch/microblaze/mm/consistent.c b/arch/microblaze/mm/consistent.c
index 45e0a1aa9357..3002cbca3059 100644
--- a/arch/microblaze/mm/consistent.c
+++ b/arch/microblaze/mm/consistent.c
@@ -81,7 +81,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	size = PAGE_ALIGN(size);
 	order = get_order(size);
 
-	vaddr = __get_free_pages(gfp, order);
+	vaddr = __get_free_pages(gfp | __GFP_ZERO, order);
 	if (!vaddr)
 		return NULL;
 
diff --git a/arch/openrisc/kernel/dma.c b/arch/openrisc/kernel/dma.c
index 159336adfa2f..f79457cb3741 100644
--- a/arch/openrisc/kernel/dma.c
+++ b/arch/openrisc/kernel/dma.c
@@ -89,7 +89,7 @@ arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		.mm = &init_mm
 	};
 
-	page = alloc_pages_exact(size, gfp);
+	page = alloc_pages_exact(size, gfp | __GFP_ZERO);
 	if (!page)
 		return NULL;
 
diff --git a/arch/parisc/kernel/pci-dma.c b/arch/parisc/kernel/pci-dma.c
index 04c48f1ef3fb..239162355b58 100644
--- a/arch/parisc/kernel/pci-dma.c
+++ b/arch/parisc/kernel/pci-dma.c
@@ -404,7 +404,7 @@ static void *pcxl_dma_alloc(struct device *dev, size_t size,
 	order = get_order(size);
 	size = 1 << (order + PAGE_SHIFT);
 	vaddr = pcxl_alloc_range(size);
-	paddr = __get_free_pages(flag, order);
+	paddr = __get_free_pages(flag | __GFP_ZERO, order);
 	flush_kernel_dcache_range(paddr, size);
 	paddr = __pa(paddr);
 	map_uncached_pages(vaddr, size, paddr);
@@ -429,7 +429,7 @@ static void *pcx_dma_alloc(struct device *dev, size_t size,
 	if ((attrs & DMA_ATTR_NON_CONSISTENT) == 0)
 		return NULL;
 
-	addr = (void *)__get_free_pages(flag, get_order(size));
+	addr = (void *)__get_free_pages(flag | __GFP_ZERO, get_order(size));
 	if (addr)
 		*dma_handle = (dma_addr_t)virt_to_phys(addr);
 
diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index 346ba382193a..9e52d1527f71 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -404,7 +404,7 @@ static void *s390_dma_alloc(struct device *dev, size_t size,
 	dma_addr_t map;
 
 	size = PAGE_ALIGN(size);
-	page = alloc_pages(flag, get_order(size));
+	page = alloc_pages(flag | __GFP_ZERO, get_order(size));
 	if (!page)
 		return NULL;
 
diff --git a/arch/sparc/kernel/ioport.c b/arch/sparc/kernel/ioport.c
index baa235652c27..f89603855f1e 100644
--- a/arch/sparc/kernel/ioport.c
+++ b/arch/sparc/kernel/ioport.c
@@ -325,7 +325,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		return NULL;
 
 	size = PAGE_ALIGN(size);
-	va = (void *) __get_free_pages(gfp, get_order(size));
+	va = (void *) __get_free_pages(gfp | __GFP_ZERO, get_order(size));
 	if (!va) {
 		printk("%s: no %zd pages\n", __func__, size >> PAGE_SHIFT);
 		return NULL;
diff --git a/arch/sparc/mm/io-unit.c b/arch/sparc/mm/io-unit.c
index 91be13935d40..f770ee7229d8 100644
--- a/arch/sparc/mm/io-unit.c
+++ b/arch/sparc/mm/io-unit.c
@@ -224,7 +224,7 @@ static void *iounit_alloc(struct device *dev, size_t len,
 		return NULL;
 
 	len = PAGE_ALIGN(len);
-	va = __get_free_pages(gfp, get_order(len));
+	va = __get_free_pages(gfp | __GFP_ZERO, get_order(len));
 	if (!va)
 		return NULL;
 
diff --git a/arch/sparc/mm/iommu.c b/arch/sparc/mm/iommu.c
index fb771a634452..e8d5d73ca40d 100644
--- a/arch/sparc/mm/iommu.c
+++ b/arch/sparc/mm/iommu.c
@@ -344,7 +344,7 @@ static void *sbus_iommu_alloc(struct device *dev, size_t len,
 		return NULL;
 
 	len = PAGE_ALIGN(len);
-	va = __get_free_pages(gfp, get_order(len));
+	va = __get_free_pages(gfp | __GFP_ZERO, get_order(len));
 	if (va == 0)
 		return NULL;
 
diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
index 1fc138b6bc0a..9171bff76fc4 100644
--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -160,7 +160,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 						 flag & __GFP_NOWARN);
 
 	if (!page)
-		page = alloc_pages(flag, get_order(size));
+		page = alloc_pages(flag | __GFP_ZERO, get_order(size));
 
 	if (!page)
 		return NULL;